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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79878c4dbe9fb001dcd10d362542878a622053583a49b12c3e592f440ac2f7c3' 
  AND token = 'cQUHwVVCwpsIPvO5kTEhAbz1yWsN7tMq56x6rGng5TM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}